Quantitative Analysis of Tannins

Tannin, also known as tannic acid, ellagic acid, astringent, can produce browning, is a natural polyphenol compounds, its structural monomer is mainly 1,2-Dihydroxybenzene, pyrogallol and phloroglucinol. Tannin is the source of astringency in wine, tannin usually comes from grape skins, grape seeds, grape stems and oak barrels.

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Sample Requirements

• Sample type: plant tissue
• Solid 2g
• Recommended to repeat more than 6 times

• Fresh/solid samples, dry ice shipping; large pieces need to be cut into 1cm

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Case Analysis

TOF LC/MS Identification and UHPLC-Online ABTS Anti-oxidant Activity Guided Mapping of Barley Polyphenols

Journal: Food Chemistry       Impact factor: 6.306 Published date: 2018       Published by: Charles Sturt University, Australia

Research Content

The polyphenol composition and antioxidant activity of seven Australian-grown barley varieties were characterized in this study. UHPLC with an online ABTS system was used to identify individual polyphenols while simultaneously measuring their antioxidant activity. The Q-TOF LC/MS system was utilized to identify the phenolic compounds that demonstrated substantial antioxidant activity.

Research Result

The variety, Hindmarsh, showed the highest total phenolic content and antioxidant activity. There was no significant difference observed amongst the other varieties in their total phenolic content, however, they did have significant variation in proanthocyanidin content and antioxidant activity (p < 0.05). Prodelphinidin B3 was the most abundant polyphenol with the highest antioxidant activity amongst all the barley varieties tested. Other polyphenols identified with antioxidant activity included procyanidin, glycosides of catechin and flavan-3-ols.

Figure 1 Polyphenol content and antioxidant activity of Australian barley varieties

Figure 2 Determination of Australian barley polyphenols (mg 100g-1) by high performance liquid chromatography at 280nm

Conclusion

Polyphenol characterization of Australian grown barley varieties demonstrated that they have significant antioxidant activity, hence, promoting the value of whole grain barley as a potential functional food ingredient.

Reference

Rao Shiwangni,Santhakumar Abishek B,Chinkwo Kenneth A et al. Q-TOF LC/MS identification and UHPLC-Online ABTS antioxidant activity guided mapping of barley polyphenols.[J] .Food Chem, 2018, 266: 323-328